1. Field of the Invention
The present invention relates to an assembly method for an endoscope image pickup unit incorporating an image pickup unit at a distal end portion of an insertion portion and an endoscope.
2. Description of the Related Art
In recent years, an endoscope in which an image pickup unit is provided at a distal end portion of an insertion portion has been widely used in a medical field such as an examination of an inside of a body cavity.
When the insertion portion is inserted into the body cavity or the like, it is possible to secure satisfactory insertion properties by reducing a size of the image pickup unit provided at the distal end portion of the insertion portion. Therefore, various assembly methods for the image pickup unit incorporated in the distal end portion of the insertion portion have been proposed.
For example, a related art of Japanese Patent Application Laid-Open Publication No. 05-269081 discloses an assembly method for an endoscope image pickup unit in which an image pickup unit is incorporated at a distal end portion of an insertion portion.
In the related art, an objective lens system and an image pickup device are assembled together to assemble an image pickup unit. The assembled image pickup unit is inserted from a rear opening portion provided at the distal end portion. The image pickup unit is fixed on an inside of the rear opening portion to thereby be assembled as an endoscope image pickup unit.
In this case, the rear opening portion is set to a size for enabling the image pickup unit to pass from a rear side.